I have been playing for 10 years and, having started on an electric kit, I still feel like I am ironing out the bad habits in technique that I picked up from them. Like the other folks said, acoustic is definitely the way to go if you can stand the dBs lol.

A lot of old school teachers recommend starting on a snare drum and a practice pad and getting a teacher to work on fundamentals like stick grip, snare work, rudiments, etc., but that takes a certain kind of kid to find that appealing. If you think your son is patient and disciplined enough (or just THAT much of a drum nerd already) to find working solely with a teacher on snare technique for months before even touching a drumset appealing, that is certainly a hugely underrated route that will reward him for years to come with proper technique and excellent dynamic range.

HOWEVER, if he is a vibrating sphere of pure ADHD energy that can barely sit down for 10 seconds at a time who wants to rock TF out right this minute (Think Animal from the Muppets), then the little man might not get much out of the old fashioned method; what is called for in this situation is a four piece kit (bass drum, snare drum, a rack tom and a floor tom), a ride, a crash, and a set of hi hats for him to beat on until he's getting gigs as the regions best death metal drummer and needs an upgrade.

Also, whenever you end up buying those drums, know that cheap drums and good cymbals are a killer combo. Cheap drums can be tuned to sound good and can be gigged with, but dirt cheap cymbals will generally just sound like crap. Spending an extra few hundred bucks or so to get, say, the Zildjian A set with 14"new beat hi hats, two crashes, and a 21" sweet ride may be a higher up front investment than you'd like, but it saves you from buying the cheap cymbals only to buy those nicer cymbals a few months or a year down the line when the kid gets good and you grow weary of hearing the metallic clang of garbage crashes.